The Role of Impact Testing in Characterizing the Toughness of Materials

The objectives of fracture toughness testing are to provide information for design, screening, and acceptance of materials. Several tests are discussed in relation to an ideal design test possessing quantitativeness and generality: slow and impact-loaded Griffith-Irwin fracture mechanics, conventional Charpy, and drop-weight tear testing (DWTT). The features and limitations of these methods are noted. Fracture mechanics is recommended for testing relatively brittle materials and DWTT and associated procedures as the best available for tough materials. Probable increased development in quantitative fracture mechanics including impact testing is discussed. For screening and acceptance, conventional Charpy testing is recommended provided that correlation with more basic tests has been established.